The 1 percent of the population that has the highest annual health expenses accounts for one-fifth of health spending . … Those in the top 5 percent account for just under half of all spending, with average annual expenditures that exceed $50,000. …

[W]hen people are separated into different age groups. In that case, the difference between the lowest and highest spenders shrinks considerably. Indeed, for decades the non-group insurance market has successfully provided voluntary coverage through a combination of medical underwriting and pre-existing condition exclusions—together the equivalent of a homeowners insurance company checking to ensure the house is not burning down before it agrees to insure that risk—and premiums that steadily rise with age.